This invention relates to vises for releasably holding an object between a pair of jaws, and more particularly, to a precision machine vise for mounting on the table of a machine, and holding an object upon which work is to be performed by the machine.
It is highly desirable for a machine vise to be easily adaptable for holding objects or workpieces of irregular shape and varying sizes, and it is particularly desirable for such a vise to be arranged for releasing one workpiece and setting up another workpiece of a substantially different size quickly and easily. Heretofore, a workpiece has been set up on a machine by providing a vise having a fixed jaw and a movable jaw each having a flat vertical surface facing the other, and the movable jaw being moved toward and away from the fixed jaw by a longitudinal threaded shaft. In this type of vise, the shaft is provided with threads having a relatively short pitch so that a high mechanical advantage is available for clamping the workpiece tightly within the vise. This arrangement is characterized by the disadvantage that in order to move the movable jaw through any substantial distance either toward or away from the fixed jaw, the threaded shaft must be rotated many times in the appropriate direction. Further, in order to properly hold an irregularly shaped workpiece, several, often complex, adapting pieces must be carefully arranged between the jaws, and occasionally must be bolted to the jaws.
Accordingly, there has existed a need for a convenient and effective machine vise having a jaw which can be moved quickly from one position to another for holding workpieces of various sizes, and having jaws which are easily adaptable for holding irregularly shaped workpieces. As will become apparent from the following, the present invention satisfies these needs.